Related documents:

This repository does not currently have the full-text of this item. You may be able to access a copy if URLs are provided below.

Abstract

Meteor radars have been used to measure the horizontal winds in the mesosphere and lower thermosphere over Castle Eaton ( 52 degrees N) in the UK and over Esrange ( 68 degrees N) in Arctic Sweden. We consider a 16-year data set covering the interval 1988 - 2004 for the UK and a 6-year data set covering the interval 1999 - 2005 for the Arctic. The signature of the 12.42-h (M-2) lunar tide has been identified at both locations. The lunar tide is observed to reach amplitudes as large as 11 ms(-1). The Arctic radar has an interferometer and so allows investigation of the vertical structure of the lunar tide. At both locations the tide has maximum amplitudes in winter with a second autumnal maximum. The amplitude is found to increase with height over the 80 - 100 km height range observed. Vertical wavelengths are very variable, ranging from about 15 km in summer to more than 60 km in winter. Comparisons with the Vial and Forbes ( 1994) model reveals generally good agreement, except in the case of the summer vertical wavelengths which are observed to be significantly shorter than predicted.